Eurosurveillance

BackgroundThe role of children in SARS-CoV-2 transmission is unclear. We investigated two COVID-19 school exposure incidents in the Helsinki area. MethodsWe conducted two retrospective cohort studies after schools exposures, with a household transmission extension. We defined a case as an exposed person with either a positive RT-PCR, or positive microneutralisation testing (MNT) as confirmation of SARS-CoV-2 nucleoprotein IgG antibodies detection via fluorescent microsphere immunoassay (FMIA). ...

In early May 2022 a global outbreak of monkeypox (MPX) started among persons without a travel history to regions known to be enzootic for monkeypox-virus. On August 8 2022, the Netherlands reported its 1000th monkeypox case representing a cumulative incidence of 55 per million population, one of the highest cumulative incidences worldwide. Here we describe the epidemiological characteristics and clinical presentation of the first 1000 monkeypox cases in the Netherlands, within the context of the...

BackgroundThe first wave of the COVID-19 pandemic in 2020 was largely mitigated by reducing contacts in the general population. In 2022 most contact-reducing measures were lifted. AimWe assess whether the population has reverted to pre-pandemic contact behaviour and how this would affect the transmission potential of a newly emerging pathogen. MethodsThe PIENTER Corona study was held every 2-6 months in the Netherlands from April 2020, as a follow-up on the 2016-2017 PIENTER3 study. In both st...

IntroductionAs the role of school-aged children was unclear at the onset of the COVID-19 pandemic, public health authorities recommended to implement infection prevention and control (IPC) measures in school settings. Few studies evaluated the implementation of these measures and their effect on SARS-CoV-2 infection rates among pupils and staff. AimTo describe the implementation of IPC measures in Belgian primary and secondary schools and assess its relation to the prevalence of anti-SARS-CoV-2...

AimsWe compared the number of non-COVID-19 deaths between April 2020 and June 2022 to the expected number of deaths based on the patterns observed in the five years prior to the pandemic in France with the aims of (a) estimating the reduction in non-COVID-19 mortality, particularly due to reduction in the circulation of other respiratory viruses during the pandemic; (b) examining the degree to which SARS-CoV-2 infection was detected and characterized as a cause of death during different periods ...

BackgroundContact tracing is conducted with the primary purpose of interrupting transmission from individuals who are likely to be infectious to others. Secondary analyses of data on the numbers of close contacts of confirmed cases could also: provide an early signal of increases in contact patterns that might precede larger than expected case numbers; evaluate the impact of government interventions on the number of contacts of confirmed cases; or provide data information on contact rates betwee...

BackgroundDuring the Covid19 pandemic, school closure has been mandated in analogy to its known effect against influenza, but it is unclear whether schools are early amplifiers of Covid19 cases. MethodsWe performed a cross-sectional and prospective cohort study in Italy. We used databases from the Italian Ministry of Education containing the number of new positive SARS-CoV-2 cases per school from September 20 to November 8, 2020 to calculate incidence among students and staff. We calculated inc...

BackgroundThe extent of SARS-CoV-2 transmission among pupils in primary schools and their families is unknown. MethodsBetween 28-30 April 2020, a retrospective cohort study was conducted among pupils, their parents and relatives, and staff of primary schools exposed to SARS-CoV-2 in February and March 2020 in a city north of Paris, France. Participants completed a questionnaire that covered sociodemographic information and history of recent symptoms. A blood sample was tested for the presence o...

BackgroundThe role of pre-school children as a source and distributor of SARS-CoV-2 infections is still unclear. Daycare facilities that care particularly for young children with limited hygiene measures may contribute to the infection dynamics during the pandemic. The aim of this study was to implement and evaluate a voluntary SARS-CoV-2 screening program in daycare facilities. MethodsThe study was conducted over a period of 4 weeks, from June 10th to July 7th 2020. The aim was to screen a rep...

BackgroundHouseholds are specific transmission settings, as they involve close and repeated contacts between individuals of different generations. Household surveys provide a unique opportunity to better understand SARS-CoV-2 transmission and the role of individual characteristics. Here, we assessed the risk of SARS-CoV-2 acquisition from household and community exposure according to age, family ties, and socioeconomic and living conditions using data from the nationwide population-based EpiCov...

BackgroundThere is limited information on the effect of age on the transmission of SARS-CoV-2 infection in different settings, including primary, secondary and high schools, households, and the whole community. We undertook a literature review of published studies/data on detection of SARS-CoV-2 infection in contacts of COVID-19 cases, as well as serological studies, and studies of infections in the school setting to examine those issues. ResultsOur literature review presents evidence for signi...

We compared vaccine effectiveness (VE) against severe COVID-19 during calendar periods from December 2021 to March 2022 when Omicron BA.1 and BA.2, respectively, were the dominating virus variants in Scania county, Sweden. We used continuous density case-control sampling matched for sex and age, and with further adjustment for differences in comorbidities and prior infection. VE remained relatively stable after the transition from BA.1 to BA.2 among people with at least three doses but decreased...

As the number of novel coronavirus cases grows both inside and outside of China, public health authorities require evidence on the effectiveness of control measures such as thermal screening of arrivals at airports. We evaluated the effectiveness of exit and entry screening for 2019-nCoV infection. In our baseline scenario, we estimated that 46.5% (95%CI: 35.9 to 57.7) of infected travellers would not be detected, depending on the incubation period, sensitivity of exit and entry screening, and t...

On February 27th, three cases of COVID-19 were reported among Norwegians that had recently returned from Lombardy, Italy. Travellers from the region rapidly became the most common source of imported infections in the earliest stage of the Norwegian COVID-19 epidemic. The situation was exacerbated by the unfortunate temporal overlap between the Norwegian winter holidays and intense epidemic spread of COVID-19 in Northern Italy, resulting in a large number of infected travellers. Here we combined ...

Since May 2022 over 20.000 human monkeypox virus (hMPXV) cases have been reported from 29 EU/EEA countries, predominantly among men who have sex with men. With over 1200 cases, and a crude notification rate of 70.7 per million population, the Netherlands was in the top 5 European countries most affected. The first national case was reported from May 10th, yet potential prior transmission remains unknown. Insight into prolonged undetected transmission can help to understand the current outbreak d...

Measures to restrict physical inter-personal contact in the community have been widely implemented during the COVID-19 pandemic. We studied determinants for infection with SARS-CoV-2 with the aim of testing the efficiency of such measures. We conducted a national matched case-control study among unvaccinated persons aged 18-49 years. Cases were selected among those testing positive for SARS-CoV-2 by RT-PCR over a five-day period in June 2021. Controls were selected from the national population ...

The potential infectiousness of asymptomatic COVID-19 cases together with a substantial fraction of asymptomatic infections among all infections, have been highlighted in clinical studies. We conducted statistical modeling analysis to derive the delay-adjusted asymptomatic proportion of the positive COVID-19 infections onboard the Princess Cruises ship along with the timeline of infections. We estimated the asymptomatic proportion at 17.9% (95% CrI: 15.5%-20.2%), with most of the infections occu...

ObjectiveThe emergence of coronavirus disease 2019 (COVID-19) required countries to establish COVID-19 surveillance by adapting existing systems, such as mandatory notification and syndromic surveillance systems. We estimated age-specific COVID-19 hospitalization and intensive care unit (ICU) burden from existing severe acute respiratory infections (SARI) surveillance and compared the results to COVID-19 notification data. MethodsUsing data on SARI cases with ICD-10 diagnosis codes for COVID-19...

BackgroundThe risk of SARS-CoV-2 (SCoV2) infection in schools and student households is typically assessed using classical epidemiology whereby transmission is based on time of symptom onset and contact tracing data. Using such methodologies may be imprecise regarding transmission events of different, simultaneous SCoV2 variants spreading with different rates and directions in a given population. We analysed with high resolution the transmission among different communities, social networks, and ...

BackgroundHigh levels of excess mortality during periods of active influenza circulation in France were observed in the years preceding the COVID-19 pandemic. Some of the factors that affect the rates of influenza associated mortality are influenza vaccination coverage levels in different population groups and practices for testing for influenza and related use of antiviral medications for various illness episodes (including pneumonia hospitalizations) during periods of active influenza circulat...